cleanup: remove the original netx implementation (#653)

This commit completely removes the original netx implementation,
which was only used by `tor`, since this has changed in
https://github.com/ooni/probe-cli/pull/652.

The original netx implementation was my first attempt at performing
network measurements using Go. It started its life inside of the
https://github.com/ooni/netx repository. It was later merged into
the https://github.com/ooni/probe-engine repository. It finally
ended up into this repository when we merged probe-engine with it.

The main issue with the original implementation is that it was
a bit too complex and used channels where they were probably not
necessary. Because of that, later I introduced a second netx
implementation, which currently lives in ./internal/engine/netx.

The current netx implementation, the third one, lives in the
./internal/netxlite package. We are currently working to replace
the second implementation with the third one, but this is happening
at a slow pace. Also, the second implementation does not have big
maintenance concerns but it's just a bit too bureaucratic to use
since it involves creating lots of `Config` structures.

The reference issue is probably https://github.com/ooni/probe/issues/1688,
since this diff has been enabled by rewriting Tor to use `measurex`
(a library living on top of `netxlite`).

internal/engine/netx/tlsdialer/tls.go

@@ -5,9 +5,6 @@ import (
 	"context"
 	"crypto/tls"
 	"net"
-	"time"
-
-	"github.com/ooni/probe-cli/v3/internal/engine/legacy/netx/modelx"
 )
 
 // UnderlyingDialer is the underlying dialer type.
@@ -20,30 +17,3 @@ type TLSHandshaker interface {
 	Handshake(ctx context.Context, conn net.Conn, config *tls.Config) (
 		net.Conn, tls.ConnectionState, error)
 }
-
-// EmitterTLSHandshaker emits events using the MeasurementRoot
-type EmitterTLSHandshaker struct {
-	TLSHandshaker
-}
-
-// Handshake implements Handshaker.Handshake
-func (h EmitterTLSHandshaker) Handshake(
-	ctx context.Context, conn net.Conn, config *tls.Config,
-) (net.Conn, tls.ConnectionState, error) {
-	root := modelx.ContextMeasurementRootOrDefault(ctx)
-	root.Handler.OnMeasurement(modelx.Measurement{
-		TLSHandshakeStart: &modelx.TLSHandshakeStartEvent{
-			DurationSinceBeginning: time.Since(root.Beginning),
-			SNI:                    config.ServerName,
-		},
-	})
-	tlsconn, state, err := h.TLSHandshaker.Handshake(ctx, conn, config)
-	root.Handler.OnMeasurement(modelx.Measurement{
-		TLSHandshakeDone: &modelx.TLSHandshakeDoneEvent{
-			ConnectionState:        modelx.NewTLSConnectionState(state),
-			Error:                  err,
-			DurationSinceBeginning: time.Since(root.Beginning),
-		},
-	})
-	return tlsconn, state, err
-}

internal/engine/netx/tlsdialer/tls_test.go

@@ -3,13 +3,10 @@ package tlsdialer_test
 import (
 	"context"
 	"crypto/tls"
-	"errors"
 	"io"
 	"testing"
 	"time"
 
-	"github.com/ooni/probe-cli/v3/internal/engine/legacy/netx/handlers"
-	"github.com/ooni/probe-cli/v3/internal/engine/legacy/netx/modelx"
 	"github.com/ooni/probe-cli/v3/internal/engine/netx/tlsdialer"
 	"github.com/ooni/probe-cli/v3/internal/netxlite"
 )
@@ -36,40 +33,3 @@ func (c *SetDeadlineConn) SetDeadline(t time.Time) error {
 	c.deadlines = append(c.deadlines, t)
 	return nil
 }
-
-func TestEmitterTLSHandshakerFailure(t *testing.T) {
-	saver := &handlers.SavingHandler{}
-	ctx := modelx.WithMeasurementRoot(context.Background(), &modelx.MeasurementRoot{
-		Beginning: time.Now(),
-		Handler:   saver,
-	})
-	h := tlsdialer.EmitterTLSHandshaker{TLSHandshaker: tlsdialer.EOFTLSHandshaker{}}
-	conn, _, err := h.Handshake(ctx, tlsdialer.EOFConn{}, &tls.Config{
-		ServerName: "www.kernel.org",
-	})
-	if !errors.Is(err, io.EOF) {
-		t.Fatal("not the error that we expected")
-	}
-	if conn != nil {
-		t.Fatal("expected nil con here")
-	}
-	events := saver.Read()
-	if len(events) != 2 {
-		t.Fatal("Wrong number of events")
-	}
-	if events[0].TLSHandshakeStart == nil {
-		t.Fatal("missing TLSHandshakeStart event")
-	}
-	if events[0].TLSHandshakeStart.DurationSinceBeginning == 0 {
-		t.Fatal("expected nonzero DurationSinceBeginning")
-	}
-	if events[0].TLSHandshakeStart.SNI != "www.kernel.org" {
-		t.Fatal("expected nonzero SNI")
-	}
-	if events[1].TLSHandshakeDone == nil {
-		t.Fatal("missing TLSHandshakeDone event")
-	}
-	if events[1].TLSHandshakeDone.DurationSinceBeginning == 0 {
-		t.Fatal("expected nonzero DurationSinceBeginning")
-	}
-}